Seat base or the like and method of making same



March 20,'1945. M. M. CUNNINGHAM 2,371,954

SEAT BASE OR THE LIKE AND METOD OF MAKING Filecwuly 26, 1940 ssheet-sne'et 1 y ff* Y vSEAT BASE OR THE` LIKE AND METHOD OF MAKING SAMEi Filed July 26, 194g :ssneetsshet 2 `March 20, 1945. 2,371,954

SEAT BASE 0R THE LIKE AND METHOD oF MAKING SAME M. M. CUNNINGHAM FiledJuly 2e, 1940 {sheets-sneer s pointed out hereinafter and as shown inthetion; Y

Fig. 2 is a fragmentary enlarged sectional view4 Patented Mar. 20, 1945SEAT BASE R TBE .'MAKIN LIKE AND METHOD 0F G SABIE Marion MorganCunningham, South Bend, Ind., assigner to Mishawaka .Rubber andv WoolenManufacturing Company,

corporatonof Indiana Application July 2e, 1940, serial No. 347,627

'i claims. (ci. 4543s) This invention relates to'improvements in basesfor seat bottoms, seat backs, or other similar purposes, and hasreference more particularly toa at pre-stretched unit of fabric orsimilar mate-y rial which may be prepared separately in a teuf sionedcondition ready for installation on the frame of a chair, seat, or thelike. The term seat base as used in the present speciiication andappended claims is intended to include a base. for seat backs as well asseat bottoms, and also a base for any other `similar purpose.

In the manufacture of chairs, davenports, automobile seats, and othersimilar articles, it is desirable to provide-a base which is light,strong,

easily applied and which will resist repeated fier-V quate yieldabilityfor ease and comfort; to avoid any appreciable sagging. to economizespace; to provide a seat base construction which is readily adaptable toa variety of seat structures and different types of mounting; to permitadvantageous combining of cushions of rubber or the like therewith; and,in general, to improve seating structures and the like and themanufacture thereof, these and other objects being accomplished ascompanying drawings, in which:

Fig. l is a plan view of a seat bas of chair bottom type embodyingoneform of the present invention, portions of successive layers beingbroken away to disclose details of the construcon the line 2'-2 ofFig.1;

Figs. 3, 4 and 5 are sectional views similar to Fig. 2 showingmodiiications of the invention;

Fig. 6"is a pian view of a chair frame with a seat base 4embodying thepresent invention mounted therein;

Fig. 'I is. an enlarged fragmentary sectional view on the line1-1 ofFig'.`6 with a portion of 8.

rubber cushion shown in position therein;

Mishawaka, Ind., a

Fig. 8 is a sectional view similar to Fig. 7 vshowing a modified form ofseat base mounting;

Fig. 9 is a plan view of a chair of tubular steel construction showing amodied seat base mounting;

Fig. 10 is an enlarged fragmentary sectional View on the line lli- I0 ofFig. 9 but with an upholstered rubber cushion mounted on the seat base;l

Fig. 111s a plan view of a chair with a further modified form of seatbase mounting;

Fig. 12 is an enlarged fragmentary View on the line I2-i2 of Fig. 11 butwith a portion of a rubber cushion mounted thereon;

Fig` 13 is a fragmentary sectional view through a chair frame with amodied form of seat base mounted thereon;

Fig. 14 is a perspective view looking 'at the bottom of an automobiletype seat base or deck with parts of the fabric broken away;

Fig. 15 is a view' also in perspective showing an end portion of anautomobile type seat structure embodying the seat base or deck of Fig.14;

Fig. 16 is an enlarged fragmentary-sectional v view on the line IG-IB'of Fig. 15 but with upholstery in position thereon;

Fig. 1'I-is a plan view of a modified base with elastic insert;

seat bottom or deck for dining room chairs,

theater seats or the like, the referenceV numeral I! indicates the seatbase as a whole which comprises aflat continuous marginal frame 20secured between two layers 2l and 22 of strong relatively non-stretchyfabric, such as duck or canvas, which are adhesively joined to oneanother and secured in a tightly stretched condition v to the frame 20.

The frame 20 is preferably of iiat steel and of suitable width torigidly withstand the strain of the stretched fabrics and to holdthesefabrics inv a tightly stretched condition in use, and this frame ismerely of suliicient thickness to insure requisite rigidity, va. widthof five-eighths of an inch and thickness of one-eighth of an inch havingbeen found quite satisfactory. It is shaped edgewise according to theshape required for the particular chair seat or chair back for which itis to be used and is prepared in an endless or conl tinuous form and ofuniform width vand thickness throughout. Obviously, vthis seat-shaped4ring sectional type of seat may be cut from flat stock or in some casesmay even be of material which may be molded in the desired shape but ispreferably made of a flat steel strip shaped to the required form andhaving the ends welded together to form an endless fiat frame. y

The two sheetsor layers 2| and 22 of fabric are coated on their innerfaces with a suitable material to insure bonding thereof securely andpermanently together, rubber compounds or compositions being preferablyused for the purpose and subsequently vulcanized as this not only`insures inseparability of and added strength to the fabric'layers butthe rubber aords elasticityand the vulcanization contributes anincreased tensioning of the fabric. l

In practice, the fabrics, before assembling are frictloned on theirinner faces with rubber compound applied by calendering and thiscompound is thus pressed into the fabric interstices and becomessecurely bonded to the fabric threads, this friction coating beingindicated at 23. Then a Vgum coating 24 is applied to the innerfrictioned face, of each fabric 2| and 22, this coating being preferablyof a suiliciently tacky character so that the two gum coatings willreadily adhere to one another upon pressing the two fabrics together,and upon vulcanization the friction sur'-4 facings and gum coatingsbecome consolidated into a unitary mass 25 with the fabric layers 2| and22 intimately combined therewith, thus producing an inseparablestructure of great strength and with the marginal frame 2U permanentlysecured between the fabric layers.

The frictioning also has the advantage that the rubbercompound isapplied while the fabric is stretched in the direction of .its lengthand the pressing of the compound into the inter- A stices stretches thefabric in a direction at right angles toits length so that the fabric asprepared myers are stitched together with strong threadclose to theframe 20 both along the inside and outside thereof as indicated atV 26and 21 respectively. Thus a. two ply fabric margin 28 with theftwofabric portions thereof vulcanized together is provided around the framewhich said margin may in somev cases trimmed olf close to the cuterstitching 2`| or be retained for use.

in mounting the seat base as required.

In making this seat base, the frictioned and' gum coated fabric layer 2|(o1 22) is laid out flat with the gumface uppermost and the marginalframe 2li laid thereon in the proper posi tion, after which the othergum coated fabric layer is' laid thereover with the gum face downward.-Then the assembled two fabrics 2| and 22 and frame 2U are passed betweenpressure rolls. so as to press the two fabrics; together in closely.adhering relation with the marginal frame venclosed therebetween.

At least one of the above mentioned pressure rolls has a surfacesufficiently cushiony'to accommodate the extra thickness at the frame 20while at the same time pressing thetwo fabrics tightly togetherelsewhere or both rolls mayhave a cushiony surface depending upon thedesired arrangement of the marginal frame on the fabrics.

If both rolls have similarly cushioned surfaces. .the fabrics 2| and 22are pressed equally onto the frame'2il or to an equal depth with respectthereto as shown at 2|a and 22' in Fig. 2, whereas if one roll` has arelatively firm surface and the other roll a cushiony surface, thefabric layer 2| engaged by the relatively firm surfaced roll will remainflat as shown at 2fb in Fig. 3 whereas the other fabric layer 22 engagedby the cushion surfaced roll will be shaped about the frame 2|) asindicated at 22b in Fig. 3, thereby providing a flat topped seat basewhich is desired in some cases. i

After the fabrics 2| and 22 and frame 20 have been thus assembled, thefabrics are stretched and stitched in any convenient manner. In practiceI employ a machine such as shown in my separate application Serial No.350,597, filed -August 3, 1940, which stretches the fabrics outwardlyaround the frame 20 and secures the fabrics rnily together immediatelyoutside the frame in the stretched condition. In that ,ma-4

chine, stretching members grasp the outer margin 28 of the fabrics andpull same outwardly around the fram'e 20 so as to stretch the fabricstightly while at the same time the two fabrics 2| and 22 are rolledtightly together close up against the outer margin of the frame 20 sothat they firmly adhere at this place. Thereafter the stitchings 26 and21 are applied around the inner and outer margins respectively of theframe 20.

After the seat base has been completed as above and the fabricsstretched and stitched along opposite sides of the frame 20,'the entirestructure is subjected to appropriate curing temperature to vulcanizethe frictioning rubber 23 and rubber coatings 24, thereby consolidatingthe rubber and by means of the vulcanized rubber inseparably bonding thefabric layers 2| and 22 together throughout their area except at thevlocation of the frame 2D which is tightly secured in a fabric andrubber pocket ,which is in effect molded around and to the frame. Aftervulcanization the area of the base within the frame 2-0 is preferablyprovided with a plurality of small perforations 29` for ventilation.

Moreover, `if desired, the assembled seat `base may, beforevulcanization thereof, be dipped, sprayed or otherwise treated withlatex to impregnate the fabric, the latex treatment serving not only towaterproof and give addtiional strength tc the fabric, but it alsocauses a shrinkage of the fabric upon vulcanization which increases thetension of the completed base.

This seat. base I9 may be mounted in various ways depending on onesparticular preference or the particular construction of the chair frameupon which it is to be mounted and the type of y cushioning. that isemployed therewith.

For example, in the structures of Figs.' 6 and 7 in which a dining roomtype of chair is shownl with conventional legs 30 and seat frame 3|, theframe 3| has cleats 32 secured to the inner face thereof near the bottomby screws 33. The seat base |9=i is made of suitable shape and size soas to lit within the seat frame 3| as shown in Fig. 6 with the marginalframe 2B overlying the cleats 32 as shown in Fig. 7 and the margin 28 ofthe seat base is trimmed off so as to leave only a narrow width thereofindicated at 28* remaining beyond the frame 2=|l as shown in'Fig. 7. Tohold the seat base.

Any desired cushion may be applied on this seat base I9? of Fig. 7,although it is preferred to employ a cushion of latexfoam such asindicated at 35 molded to shape to extend down into the chair well andrest on the seat base and with overhanging margins 36 overlying theframe 3|, such cushions being customarily formed with a plurality ofcavities 31 in the under side. This cushion 35 is preferably cemented tothe top face of the seat base I9a and has a tape 38 extendingtherearound and cemented to the overhanging portion 36 and this tapeextends downwardly around the chair frame 3| and is tacked thereto atintervals as indicated at 39. The' cushion is then covered in the usualmanner with an upholstery covering (not shown) whichA is fastened to theframe 3| below the attaching strips 38'.

In cases such as in Fig. '7 wherein a rubber cushion is to be attachedto the seat base the top fabric 2|, before assembling in the seat baseis preferably frictioned on both sides with rubber compound, instead ofonly on the under side, so that in the finished seat base the topthereof is rubber surfaced, as at 40 inFig. 7, to insure a better bondthereto of the cement by which the this seat base on the cleats, a fewtacks 34 may seat frame 50, the marginal frame 26 being provided withopenings at intervals around to rerubber cushion is attached to the seatbase.

When the rubber cushion and seat base are thus force the cushion andvthe cushion to give added stability to the base thereby affording anespecially advantageous and desirable seat cushioning.

.Another seat base mounting, of suspended form, shown in Fig. 8 isespecially simple and convenient. In this form no cleats are employed asat 32 in Fig.. 7, the seat base, indicated at I9 being suspendeddirectly from the chair frame by means of the marginal extension 28 ofIn this case the seat base I9 is inserted in the chair well within-themarginal' ange 28 upturned against the inner face of the chair frame andthis marginal flange 28 is Secured to the frame 3|,by'tacks 4I spacedpreferably about one inch apart. In lthis type of `mounting the frame 29is instrumental in disas in the structure of Fig."1.

- Figs. 9 and 10 illustrate a seat base and cush Vion for steel tubefurniture or sea-ts. In .this

, embodiment a steel tube type of chair seat frame 42 is provided with aplurality of inwardly projecting tabs 43 welded to the frame and each ofthe tabs is provided with an opening 44 to freely receive a screw. Aseat base I9, such as previously I described, is provided, the frame 28of which has a plurality of threaded op:nings 45 adapted to registerwith the openings 44 of the` A foam sponge cushion 46 is cementedl tabs'43. to the base I9 after which upholstermg. cloth 41 gins adhesivelysecured to the under side of the complete 'units similar to that of Fig.13 mayalso` base as indicated at 4s in Fig. 1o. The base withupholstered cushion assembled thereon is then mounted in place and issecured in position with screws 49.

In the structure illustrated in Figs. 11 and 12 the seat base I9 ismounted directly on the chair ceive the wood vscrews 5| which areengaged through these openings and into the 'frame 50, and the extendedmargin 28 of the seat base I9 is trimmed Ioff as indicated at 28b tosubstantially coincide with' the outery dimensions of the chair frame50. 'A foam sponge cushion 53 is adhesively secured to the base I9 andhas a tacking tape 54 adhesively secured therearound and is tacked to'the frame as at 55.

Padding other than foam sponge may'of course be employed in thisvstructure of Fig. 12 as well.

as in other structures if desired,` or in vsome structures, thecushioning may be entirely omitted. For example, as shown in Fig, 13the-seat base I9, made with a flat top as shown in Fig. 3, is merelycovered with upholstery cloth 56 and secured to the top of the chairseat frame 51.

For mounting this seat base on the frame 51 a tacking strip 56 ispreferably stitched or other..

wise secured to the under side of the seat base' I9 at a proper locationto extend Adownwardly along the inner side of the seat frame 51 land ismerely tacked to the seat frame as indicated at 59. This tacking stripmay be conveniently attached as shown-in Fig. 13 with the same stitching26 that is employed to secure the two fabric layers 2| and 22 togetheralong the inner margin of the frame 20.

' The upholstery cloth 56 may be applied in any desired manner as forexample,as' shown in Fig. 13, the two ply fabric margin 28 of the seatbase may be trimmed off to leave only a narrow. width 28c suitable forstitching beyond the frame 20 and the edge of the upholstery fabric56may be stitched to this narrow extended edge 28c y as at'6I.preferablywith a binding strip 62 enclosing the edge structure andattached with the same stitching 6I.

This structure of Fig. 13 -mayof course be completely prepared with thecovering `of upholstery cloth 56 ready for mounting and provides aconvenient replacement unit'because of its complete assembly andconvenience of attachment, it being understood of course, that be madewith padding or a rubber cushion between the seat base I9 and upholsterycloth 56 and likewise attachedto' the chair frame witha tacking strip 58or in some similar manner. M`Ioreover, the upholstery cloth `56, insteadof t nersomewhat similar to that shown in Fig. 10.

Figs. 14, l5 and-'16 illustrate anv automobile type seat cushion-using aseat base 63 embodying is then applied over the cushion andthe marthepresent invention. In this construction an -the fabric layers 2| and 22are vsecured tothe framezn in Fig. 1, bom layers s1 and es beingmetisses with rubber and gumfccated on their inner faces, adhesivelycombined throughout their area, stretched tautly and stitched along theinner and outer sides of the frame 64, as indicated by numerals 25* and26 respectively, and thereafter vulcanized all as explained inconnection with Fig. 1. Obviously the lower fabric layer 58 is Aslittedor cut away as at 69 to strad'dle the ends of the struts 65 and theinner stitching 26*L is interrupted at the struts.

The two ply fabric deck thus produced is prol vided with ventilationapertures which may be ber before vulcanization for this purpose, and avtape 18 is cemented around and to the foam sponge cushion and turnedunder the seat base ll and secured to the under side/thereof as at 18 tocombine the-.cushion and base into a substantially integral assembly.

This combined cushion and base may be supported in any desired manner,as forfexample by a sheet metal frame or riser 80 which is provided withan inturned flange 8| about its upper edgeto support the base andcushion assembly. A plurality of bendable lugs 82 are provided aroundthe top of the riser and are bent inwardly at their upper ends andforcedinto the cushion 11 and over the margin of the seat base 83 asshown at Elin Fig. 16 to secure the cushion assembly to the frame orriser 80. A tacking -strip 84 is provided along the lower edge of the Insome cases where an extended' fabric margin 28 is not requned entirelyaround the seat 'base I9 a single piece 95 offabric may be employed,instead of the two pieces 2| and 22, and folded along one 'length of theframe 28.V as

. shown at 86 in Fig.f4, in which case, of course,

the fabric must be of an area corresponding approximately to thecombined area of the fabric layers 2l and 22. In this form the singlesheet 95 of fabric is frictioned and gum coated on one side, a stieningframe is laid on one halt of the gummed face of the fabric so treatedand the other half of the fabric is then folded over to enclose theframe between the laminations of the fabric.J Thereafter the fabric ispressed together, tensioned, sewed, vulcanized, and perforated as abovedescribed for the structure of Fig. l, except that the outside stitching21 is Y omitted along the folded edge '88.

Rubber inserts may be Dprovided in .these A various seat bases, one formof which is shown in the Aseat base 81 of Figs. 17 and 18 which show anautomobile type of seat base. This seat base 81 is made with two fabriclayers 88 and 89 stretched on a marginal frame 90 and stitched andvulcanized together in exactly the same manner as in' the structure ofFigure 1. The fabric layers .88 and 89 however are correspondingly cutaway to provide a matching wide U-shaped opening 5| in each extendingacross the rear of the seat basev and forwardly at each side andpreferably of -centrally reduced width at the back as shown in Fig. i7,and a similarly U-shapedpiece 92 of sheet rubber but of greater widthand length is permanently secured along its edges between the opposedfabric layers 88 and 89 as shown at 931m Fig. 18 to provide an elasticfiller or insert for the opening 9|.

Temporary bridgings 94 may be provided across the insert 92 to'preventundue stretching of the Instead of coating the inner faces of thefabrios 2| and 22 with ordinary gum, they may have a coating of rubber,compounded with a'. blowing agent, calendered thereon which in thesubsej quent vulcanization-is expanded by the blowing agent to producesponge rubber in a manner well known 1n the art.

Thus the seat base is formed as shown in Fig. 5 with a sponge filler 81between and separating the fabrics 2| and 22, thereby affording asoftness j of seat base which is desirable for some purposes.

Moreover, since the fabric layers 2| and 22 are stitched together atopposite sides of the frame 20 at 2B and 21, prior to vulcaniza'tion thesponging of the rubber and spreading ofthe fabrics 2l and 22 thusimposes an increased tension on these fabrics. The base, thus formed,may, of course, be provided with perforations for ventilation -like theperforations 28 of the base of The above seat base may be usedadvantageously in many other ways in making chairs, or the like, and theresiliency of the marginal frame 20 may be utilized to give yieldabilityto the seat bottom or seat back. For example, in Figs. 19 and 20 a chairis shown wherein the seat bottom and the seat back are both providedwith a fabric seat 'deck constructed with a marginal frame 28 in themanner above described, these marginal frames being of spring steel andmounted to permit yielding thereof to pressure applied on the seatbottom 'and the seat back.

While I have shown the seat base herein in a preferred form and asapplied to seat bottoms. it is to be understood that i-t may be employedfor seat backs or elsewhere and that various changes and modificationsmay be made without ldeparting from the spirit of the invention, the

scope of which is to be determined by .the apall exceptthe marginalVportions of the rubber insert 92, to avoid adhesion to therubber of theApended claims. am

I claim as my inventioni 1. A pre-formed unit for seat base purposes orthe like, said unit comprising a marginal seat base frame and-two layersof fabric or the like having the frame interposed therebetween, saidframe being flat in the plane of the unit, said layers of fabric or thelike being tautlyI stretched on the frame and bonded together by avulcanized rubber compound. i

2. A pre-formed unit forseat base purposes or the like', said unitcomprising two layers of fabric or the like with a flatf marginalframeinterposed therebetween, said frame being of little thickness butof substantial horizontal width in the plane of the unit, said layersbeing stretched taut within the area bounded by the frame and bondedtogether by a vulcanized rubber compound at the inner and outer sides orthe frame.

3. A pre-formed unit for seat base purposes or the 1ike,.said unitcomprising two layers of fabric or the like with a 'ilat marginal frameinterposed therebetween, said frame being of little thickness but ofsubstantial horizontal width in the plane of the unit, said layers beingstretched taut within the areaI bounded by the frame and stitchedtogether along the inner and outer sides of the frame Vand said layersbeing bonded together at the inner and outer sides of the frame by avulcanized rubber compound and the stitches bonded to the layers by thevulcanized rubber compound.

4. A pre-formed unit for seat base purposes or the like, said unitcomprising two layers of fabric or the like with' a marginal frameinterposed therebetween, said layers being stretched taut within thearea bounded by said frame and bonded together by an intermediate layerof vuli canized sponge rubber.

5. In a seat or the like, asupporting structure, a resilient seat basecomprising a surrounding marginal frame and two layers of fabric or thelike having the frame interposed therebetween and being tautly stretchedon the frame and secured together in face to face relationship,

means securing the marginal fraxneto the sup- 4 porting structure, and aseat cushion or the like of spongy rubber secured to the upper side ofsaid 'seat base.

6. In a seat or the like, a supporting structure, a resilient `seat basecomprising a surrounding marginal frame and two layers of fabric or thelike having the frame interposed therebetween and being tautly stretchedon the frame and secured together in face to face relationship, meanssecuring the marginal trame to the supporting structure, and a. seatcushion or the like of spongy rubber secured to the upper side of saidseat base with the marginal frame of the latter underlying the margin ofsaid cushion.`

7. The method of making a seat base unit or the like, which comprisescoating the inner faces of two fabric or like layers with a vulcanizableMARION MORGAN CUNNINGHAM.

